Functional Orientation of Biochemical Processes in Female Beluga × Sterlet (<Emphasis Type="Italic">Acipenser ruthenus</Emphasis> Linnaeus, 1758 × <Emphasis Type="Italic">Huso huso</Emphasis> Linnaeus, 1758) Hybrids in the Reproductive Cycle

The article reports data on the dynamics of blood parameters and parameters of protein, fat, and water–salt metabolism in female starlet × beluga hybrids kept under artificial conditions in the period of reproductive cycle. Gonad maturation in female hybrids in the artificial environment causes clear changes in the biochemistry of blood and of urine.     

Embryology of Plagiopteron suaveolens Griffith (Plagiopteraceae) and its systematic implications

A study of the embryology of Plagiopteron suaveolens Griffith is presented in order to evaluate the affinities of the genus. Anther wall formation is of the dicotyledonous type. The anther tapetum is glandular and its cells become two to four nucleate. Cytokinesis in the microspore mother cell is simultaneous and the resultant tetrad is tetrahedral. The mature pollen grains are two-celled. The anther has 4-locules at anthesis. The ovule is anatropous, bitegmic and weakly crassinucellate with only one cell-layered parietal tissue. The micropyle is zig-zag in section and formed by both inner and outer integuments which are three and three to four cell layers thick respectively. The megaspore archesporium is one-celled and the embryo sac development is of the Polygonum type. An endothelium is formed with early disintegration of nucellar tissue. The antipodals multiply to 15 to 20 cells. Embryological evidence supports the placement of Plagiopteron in its own family, Plagiopteraceae, with closest relationship with Celastraceae and close relationship with Elaeocarpaceae, Rhizophoraceae and some families of the Geraniales.     

Carboxyl terminal of rhodopsin kinase is required for the phosphorylation of photo—activated rhodopsin

Human rhodopsin kinase (RK) and a carboxyl terminus-truncated mutant RK lacking the last 59 amino acids (RKC) were expressed in human embryonic kidney 293 cells to investigate the role of the carboxyl terminus of RK in recognition and phosphorylation of rhodopsin.RKC,like the wild-type RK,was detected in both plasma membranes and cytosolic fractions.The Cterminal truncated rhodopsin kinase was unable to phosphorylate photo-activated rhodopsin,but possesses kinase activity similar to the wild-type RK in phosphorylation of small peptide substrate.It suggests that the truncation did not disturb the gross structures of RK catalytic domain.Our results also show that RKC failed to translocate to photo-activated rod out segments.Taken together,our study demonstrate the carboxyl terminus of RK is required for phosphorylation of photo-activated rhodopsin and strongly indicate that carboxyl-terminus of RK may be involved in interaction with photo-activated rhodopsin.     

丙型肝炎病毒核心蛋白抑制乙型肝炎病毒转录的分子机理

为研究丙型肝炎病毒 (HCV)核心蛋白抑制乙型肝炎病毒 (HBV)表达的分子机理 ,从HCV和HBV共感染中国病人血清中分离了 5个含HCV 5′非编码区 ( 5′NCR)和核心区 (CR)cDNA序列的克隆 .序列比较和系统发育分析显示 :从共感染病例中分离的HCV序列与其它已发表的从单独HCV感染病例中分离的序列没有显著差异 .共转染实验证实采用从其中 1例共感染病人中分离的核心蛋白cDNA基因所表达的核心蛋白 ,可抑制HBV表面抗原 (HBsAg)和HBVe抗原 (HBeAg)的表达 ,缺失突变分析说明HCV核心蛋白的C端疏水区对这种抑制作用是必需的 ,报道基因产物分析进一步说明了HBVC启动子和增强子Ⅱ是HCV核心蛋白的效应靶序列之一 ,而HCV核心蛋白在肝细胞和非肝细胞中均对HBV和其他细胞和病毒的基因的转录起负调节作用 .因此 ,认为HCV核心蛋白是一种多功能的负调节因子 ,与HCV和HBV以及HCV与细胞之间的相互作用密切相关     

Induction of apoptosis and change of bcl—2 expression in macrophage Ana—1 cells by all—trans retinoic acid

Macrophage cells play an important role in the initiation and regulation of the immune response.All-trans retinoic acid (ATRA) and its natural and synthetic analogs (retinoids)affect a large number of biological processes.Recently,retinoids have been shown promise in the therapy and prevention of various cancers.However,many interesting questions related to the activities of retinoids remain to be answered:(I) Molecular mechanisms by which retinoids exert their effects;（Ⅱ)why the clinical uses of retinoids give undesirable side effects of varying severity with a higher frequency of blood system symptoms;(Ⅲ)little is known for its impacts on macrophage cells etc.We set up this experiment,therefore,to examine the apoptosis of ATRA on macrophage Ana-1 cell line.Apoptosis of the cells was quantitated,after staining cells with propidium iodide(PI),by both accounting nuclear condensation and flow cytometry.When the cells were treated with ATRA at or higher than 1μM for more than 24h,significant amount of the apoptotic cells was observed.Induction of apoptosis of Ana-1 cells by ATRA was in time-and dose-dependent manners,exhibiting the similar pattern as the apoptosis induced by actinomycin D (ACTD).ATRA treatment of Ana-1 cells also caused the changes of the mRNA levels of apoptosis-associated gene bcl-2,as detected by Northern blot analysis.The temporal changes of bcl-2 expression by ATRA was also parallel to that by ACTD.In conclusion,ATRA can induce apoptosis in macrophage cells,which may be helpful in understanding of immunological functions retinoids.     

A topological model for chromatin transcription and a role for nucleosome linkers

There is a good deal of evidence that transcribing RNA polymerase may translocate across nucleosomes without their displacement and (or) rearrangement. A topological model for RNA chain elongation on a nucleosome is considered here. A new mechanism of RNA polymerase translocation is suggested in order to avoid the steric hindrances inherent in the model. It is shown that a transcribed nucleoprotein fiber should be interrupted by protein-free DNA stretches (nucleosome linkers) to allow release of nascent RNA. Possible verifications and consequences of the model are discussed.     

Myosin accelerates synaptic vesicle recycling in the motor nerve endings

Neurotransmitter release and exocytosis of synaptic vesicles in the motor nerve endings of the frog cutaneous-pectoris muscle were studied using electrophysiological and optical methods under the conditions of inhibition of the myosin light-chain kinase and non-muscle myosin by the specific inhibitors ML-7 (12 μM) and (–)-blebbistatin (100 μM). At high-frequency stimulation (20 pulses/s), these inhibitors strengthened suppression of transmitter release during the first 20–25 s and slowed down the release of the fluorescent dye FM 1-43. The obtained results indicate that myosin accelerates rapid synaptic vesicle recycling upon high-frequency stimulation.     

一个含端粒序列的水稻BAC克隆的分析和定位

对一个含 (TTTAGGG) _n 同源序列的水稻BAC克隆 (BAC2 )进行了分析 ,揭示出水稻近端区DNA的组成 .BAC2的插入片段中除含有大量的以串联形式存在的称之为TA35 2序列的卫星DNA外 ,还含有TTTAGGG或其变体组成的简单重复 .荧光原位杂交 (FISH)将含 (TTTAGGG) _n 序列的 0 .8kbPstⅠ片段定位在至少 5对染色体的端粒区 .通过对BAC2中低拷贝序列的RFLP分析 ,BAC2被定位在水稻第 6号染色体端部 .这些结果说明水稻的端粒序列可能也是TTTAGGG或其变体构成的简单重复 ,而与其相连的卫星DNATA35 2则属于端粒相关序列 .     

微藻光密度与细胞密度及生物质的关系

以四种常见微藻,小球藻(Chlorella sp.XQ-20044)、栅藻(Scenedesmus sp.SS-200716)、绿球藻(Chlorococcum sp.)和螺旋藻(Spirulina sp.CH-164)为实验材料,用梯度稀释法测定对数生长期不同浓度藻液的光密度(OD)、细胞密度和生物质干重(DW),在光自养分批培养模式下对4种微藻进行OD-波长(350—800 nm)扫描,同时测定细胞密度和生物质干重,分析藻液OD与细胞密度、生物质干重的关系。结果表明:在任何波长下,对数生长期的4种微藻细胞密度与OD值、生物质干重与OD值的变化都不成比例,波长不同其拟合曲线偏离直线的程度不同。但是,在435 nm处这种关系最接近直线,可以用直线方程近似描述(R20.98),其它波长处细胞密度-OD、干重-OD的关系都可以用二项式方程很好地描述(R20.99)。因此,光密度法适用于连续和半连续培养,可以用435 nm处测得的OD值计算细胞密度与干重。但是在分批培养模式下,4种微藻DW/OD比值随着培养时间均逐渐上升。小球藻DW/OD540为0.19—0.44 g/L,栅藻DW/OD540为0.36—0.53 g/L,绿球藻DW/OD540为0.48—0.75 g/L,螺旋藻DW/OD560为0.46—0.74 g/L,因此分批培养模式下采用测定藻液OD值反映细胞密度和生物质的方法不适用,只有直接测定细胞密度和生物质才是准确的。研究结果为正确使用分光光度法监测微藻生长提供依据。     

红火蚁三龄、四龄幼虫肠道菌菌群多样性分析

昆虫体内细菌的多样性对昆虫的消化、营养的吸收、生长发育繁殖具有至关重要的作用.本研究利用16S rRNA基因序列,构建内生菌16S rRNA克隆文库,探明红火蚁3龄幼虫和4龄幼虫种群体内微生物菌群结构并加以对比,采用Miseq高通量测序的方法揭示红火蚁3龄幼虫与4龄幼虫肠道菌的相似性和差异性.结果表明:红火蚁高龄幼虫的...